Toggle clamp with adjustable guide



Sept. 22, 1964 A. W. M PHERSON TOGGLE CLAMP WITH ADJUSTABLE GUIDE FiledApril 2, 1962 EEEE @i /fj@' ATTORNEYS United States Patent Office3,l49,832 Patented Sept. 22, 1%64 This invention relates to animprovement in a toggle clamp construction of the general type disclosedin United States Letters Patent 2,054,572 and more particularly to theprovision of an adjustable guide means for the clamp bar which resultsin rigid lateral stability.

In many toggle clamp applications it is necessary or highly desirable tohave a lateral stability for the clamp bar which is inherently difiicultto provide with conventional construction due to clearances required forfreedom of clamp bar travel and related tolerances. If the conventionalelements connected by toggle pivots are held together in a suflicientlytight fit to provide a high degree of lateral stability to the clamp barin its clampng position, the operation of the clamp in its releasing andengaging travel becomes unduly stiff; furthermore, the connectingelements normally available to laterally stabilize the clamping bar areusually so located as to have a high degree of mechanical disadvantagein retaining the clamping end of the bar against lateral displacement.

The present improved construction incorporates extensions toconventional clamp base elements adapted to provide a guide for theclamp bar engaged during its final closing travel advantageously locatedfor lateral stabilizing purposes together with an adjustable take-up forthe spacing between opposed guide surfaces in order to provide exactlythe desired closeness of fit.

These and other objects of the present invention will be best understoodby reference to the following description of a preferred embodimentillustrated in the drawings wherein:

FIG. 1 is a side elevation of the improved clamp assembly;

FIG. 2 is an end elevation thereof; and

FIG. 3 is a sectional view taken along the line 3--3 of FIG. 1.

Conventional elements of the toggle clamp include a central clamp barpivotally connected at 11 to a pair of spaced base plates 12, havingattachment holes 13 for connection to a fixture or like mounting. A pairof handle elements 14 welded together at the top are formed as a yoke atthe bottom spanning the base plate 12 and pivotally connected thereto at15 as well as at an intermediate point 16 to a link stop member 17having side elements 18 pivotally connected at 19 within the yokeportion of the handle to the clamp bar 10.

The assembly is shown in clamping position with the stop member 17registering against the clamp bar at 20 and the pivotal connections 15,19 and 16 in substantial alignment. Unlocking and opening of the clampis accomplished by moving the top of the handle to the left as seen inFIG. 1 thereby breaking the toggle linkage and causing the clamp bar 10to raise as the handle is moved progressively back.

The base plate elements 12 are provided with forward guide extensions21, beveled at their upper ends 22 as best shown in FIG. 3 to guidinglyreceive the clamp bar 10 as it moves downwardly into clamping position.An adjustment bolt 23 permits the base plate extensions 21 to be drawntogether to a zero clearance relation with the clamp bar 10 and withprecisely the right contact pressure to assure positive stabilizingagainst lateral play without undue interference with the release of theclamp. As soon as the guide bar 10 has cleared the guide extensions 21in opening movement any frictional contact pressure with the guideextensions is eliminated and the assembly is free to move to a wide openposition without any resistance from the guide elements.

It will be understood that the base could take other forms, for exampleas adapted for attachment to a horizontal surface, and that othermodifications might be resorted to without departing from the scope ofthe invention as defined in the following claims.

I claim:

1. A toggle clamp comprising base, clamp bar, handle and link elementspivotally inter-engaged to cause said clamp bar to move to atoggle-actuated locked clamping position, characterized by rigidstationary laterally adjustable guide means for engaging the sides ofsaid clamping bar element to provide lateral stability thereto in itsclamping position relative to its plane of actuation.

2. A toggle clamp as set forth in claim 1 wherein said guide meanscomprise extensions of said base plate elements projecting outwardly ofthe inter-engaging toggle connections toward the clamping end of saidclamping bar element.

3. A toggle clamp as set forth in claim 2 wherein said guide extensionsare provided with beveled edges for leading said clamp bar elementbetween said guide extensions as it approaches final clamping position.

4. A toggle clamp as set forth in claim 2 including adjusting means fordrawing said extensions toward each other in a close fittingrelationship with said clamping bar element.

5. A toggle clamp as set forth in claim 4 wherein said adjusting meanscomprises a bolt passing through said extensions at a positionimmediately adjacent the final clamping position of said clamping barelement.

6. A toggle clamp mechanism comprising a pair of spaced base plateelements, a central clamp bar extending between said base plateelements, a first pivotal connection between one end of said clamp barand said base plate elements, a handle having a yoke spanning said clampbar and base plate elements, a second pivotal connection between theends of said yoke and said base plate elements, a pair of link elementsextending within said yoke, a third pivotal connection between one endof said link elements and said clamp bar, a fourth pivotal connectionbetween the other end of said link elements and said yoke, said thirdpivotal connection being intermediate and alignable with said second andfourth pivotal connections when said clamp arm is in clamping position,said base plate elements having guide extensions for receiving saidclamp bar outboard of the respective pivotal connections, and anadjustable bolt for drawing said guide extensions together to a closelyfitting relationship with said clamp bar when the latter is in clampingposition.

References Cited in the file of this patent UNITED STATES PATENTS2,054,572 McKenna Sept. 15, 1936 2,577,029 Moorehead Dec. 4, 19513,035,831 Blatt May 22, 1962

6. A TOGGLE CLAMP MECHANISM COMPRISING A PAIR OF SPACED BASE PLATEELEMENTS, A CENTRAL CLAMP BAR EXTENDING BETWEEN SAID BASE PLATEELEMENTS, A FIRST PIVOTAL CONNECTION BETWEEN ONE END OF SAID CLAMP BARAND SAID BASE PLATE ELEMENTS, A HANDLE HAVING A YOKE SPANNING SAID CLAMPBAR AND BASE PLATE ELEMENTS, A SECOND PIVOTAL CONNECTION BETWEEN THEENDS OF SAID YOKE AND SAID BASE PLATE ELEMENTS, A PAIR OF LINK ELEMENTSEXTENDING WITHIN SAID YOKE, A THIRD PIVOTAL CONNECTION BETWEEN ONE ENDOF SAID LINK ELEMENTS AND SAID CLAMP BAR, A FOURTH PIVOTAL CONNECTIONBETWEEN THE OTHER END OF SAID LINK ELEMENTS AND SAID YOKE, SAID THIRDPIVOTAL CONNECTION BEING INTERMEDIATE AND ALIGNABLE WITH SAID SECOND ANDFOURTH PIVOTAL CONNECTIONS WHEN SAID CLAMP ARM IS IN CLAMPING POSITION,SAID BASE PLATE ELEMENTS HAVING GUIDE EXTENSIONS FOR RECEIVING SAIDCLAMP BAR OUTBOARD OF THE RESPECTIVE PIVOTAL CONNECTIONS, AND ANADJUSTABLE BOLT FOR DRAWING SAID GUIDE EXTENSIONS TOGETHER TO A CLOSELYFITTING RELATIONSHIP WITH SAID CLAMP BAR WHEN THE LATTER IS IN CLAMPINGPOSITION.